Inferior Rectus Muscle Restriction after Sub-Tenon's Anesthesia

Dear Editor, Sub-Tenon’s anesthesia (STA) is widely used for regional orbital anesthesia. Complications of STA are rare but include inferior rectus muscle restriction [1-3]. There have been no reports of inferior rectus restriction after STA in Korea. We encountered a patient with inferior rectus muscle restriction after STA who eventually required surgical treatment and report the case herein. A 64-year-female visited our clinic in May 2013 for diplopia in the whole field of vision. She had undergone cataract surgery under local anesthesia using STA with 2% lidocaine without hyaluronidase at another clinic in March 2013 and complained of diplopia beginning in the immediate postoperative period. She had no systemic disease or preoperative history of diplopia or strabismus. She demonstrated 20 prism diopters hypotropia in the left eye in the primary position with limited elevation. Visual acuity was 20 / 20 in both eyes. Blood tests, including thyroid function tests and anti-acetylcholine receptor antibody, were within the normal ranges. No abnormal extraocular muscle findings were seen on orbital computed tomography. The diplopia increased to 30 prism diopters hypotropia in the left eye over five months postoperatively. Surgical treatKorean J Ophthalmol 2015;29(2):142-143 http://dx.doi.org/10.3341/kjo.2015.29.2.142